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Test Info: Warnings
- This test has a WPT meta file that expects 1 subtest issues.
- This WPT test may be referenced by the following Test IDs:
- /css/css-scroll-snap/snap-fling-in-large-area.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<html>
<head>
<title>Fling within a large target is not interrupted by scroll snap</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-actions.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<script src="/dom/events/scrolling/scroll_support.js"></script>
</head>
<body>
<style>
main {
scroll-snap-type: y;
overflow: auto;
height: 100vh;
}
div {
scroll-snap-align: start;
width: 80vw;
height: 800vh;
background: yellow;
border: solid black 3px;
}
</style>
<main id="scroller">
<div></div>
</main>
<script>
promise_test(async (t) => {
await waitForCompositorReady();
const scroller = document.getElementById("scroller");
assert_equals(scroller.scrollTop, 0, "scroller not initially scrolled");
let initial_scroll_top = scroller.scrollTop;
let last_scroll_top = initial_scroll_top;
const scroll_listener = () => {
assert_greater_than_equal(scroller.scrollTop, last_scroll_top,
"fling did not move backwards.");
last_scroll_top = scroller.scrollTop;
}
scroller.addEventListener("scroll", scroll_listener);
// We expect pointercancel to be triggered when scrolling starts due to
// the touch-fling. If we instead get a pointerup event, we know that
// scrolling isn't happening and we can immediately fail the test instead
// of waiting for a timeout.
const pointer_promise = () => {
return new Promise((resolve, reject) => {
document.addEventListener("pointerup", reject, { once: true });
document.addEventListener("pointercancel", resolve, { once: true });
});
};
try {
const scrollend_promise = waitForScrollendEventNoTimeout(scroller);
await touchFlingInTarget(/*pixels_to_scroll*/100, scroller, "down");
await pointer_promise;
await scrollend_promise;
} catch(e) {
assert_unreached("Failed to trigger touch fling.");
}
assert_greater_than(last_scroll_top, initial_scroll_top,
"received at least one scroll update.");
assert_greater_than_equal(scroller.scrollTop, last_scroll_top,
"fling did not move backwards at the end of the scroll.");
}, "fling within a large area is not interrupted by scroll snap");
</script>
</body>
</html>